There are many factors to consider in SOC design. However the three most important constraints are the process corner, temperature, and power supply. The conventional SOC design methods use electronic design automation tools which assume a power supply voltage on certain combination or range of supply voltage while working with changing process corner and temperature parameters.
The power supply design is done independently from the SOC process corner and temperature design process. Without the integration of the power supply design, several problems arise in SOC production, including long circuit design times, large silicon area, high power consumption and high material and labor costs.
Additionally, this separate design approach gives rise to the worst-speed and worst-power cases. The worst-speed case or performance bottleneck occurs at the lowest supply voltage, highest temperature, and slowest process corner. From the worst-speed case the following problems arise: a lower supply voltage head room and slower transistor speed, a larger transistor W/L ratio is used to compensate, and a higher die cost. In the opposite scenario, the worst power case or power consumption bottleneck occurs at the point of the highest supply voltage, lowest temperature and fastest process corner. This case creates the following problems: a larger current from higher transistor speed and higher supply voltage, a higher thermal coefficient package or heat sink used, and a higher package cost.
Accordingly it is desirable to reduce the time, size, and cost of circuit design and eliminate the worst case scenarios or bottlenecks that appear in the design phase and during the shift to the application phase.